I drove down to Framingham AAA, which provides RMV services on Saturday, and they said, nope, go online and do it there, print the receipt and give it to your insurance. As near as I can tell, you don't actually turn over the plates to anyone any more? Really? *shrug* I still need to communicate with my insurance agent (also AAA), but they are closed at the moment. I'll try calling on Monday and see if I can email them the .pdf receipt. Because then I could do the whole thing without leaving the house (honestly, I don't know why I had my mother-in-law send me the plates, but perhaps we'll need them at some point in this process).